BUG#23427 incompatible ABI change in 5.0.26?
   - Use the icheck tool if avaliable and compare the current mysql.h to a version
controlled reference file 


BitKeeper/etc/ignore:
  Added include/check_abi include/mysql_h.ic to the ignore list
configure.in:
  Look for icheck in configure
include/Makefile.am:
  Add rule to build mysql_h.ic if icheck is avaliable
  Add rule to compare mysql_h.ic to the version
  controlled reference file mysql_h_abi.ic
include/mysql.h:
  Add comment about taking care when editing mysql.h
  Add example how to add reserved fiels in the structs to
  allow for features to be added without breaking ABI
include/mysql_h_abi.ic:
  Add new file describing the libmysqlclient ABI used as a reference to detect ABI breakage